Combustion apparatus

ABSTRACT

AN APPARATUS FOR ESTABLISHING CONTROLLED TEMPERATURES AND OXYGEN CONTENT OF A GAS FOR REMOVAL OF DEPOSITS FROM EQUIPMENT BY OXIDATION. A CHAMBER IN WHICH THE EQUIPMENT TO BE CLEANED IS POSITIONED IS ADAPTED WITH GAS CIRCULATING DUCTWORK AND WITH A BURNER FOR THE INTRODUCTION OF HOT GASES OF CONTROLLED OXYGEN CONTENT.

June 6, 1972 D'ARCY ETAL 3,667,744

COMBUSTION APPARATUS Filed Aug. 20, 1970 INVENTORS R. M. DARCY J. C.BIRTELL YE. P. HENSLEY R.C.PRYOR A T TORNEYS U.S. Cl. 26340 R United States Patent() 3,667,744 COMBUSTION APPARATUS Robert M. DArcy, James C. Birtell, and Emmery P.

Hensley, Borger, Tex., and Robert C. Pryor, Bartlesville, Okla, assignors to Phillips Petroleum Company Filed Aug. 20, 1970, Ser. No. 65,533

Int. Cl. F27b 3/10 11 Claims ABSTRACT OF THE DISCLOSURE An apparatus for establishing controlled temperatures and oxygen content of a gas for removal of deposits from equipment by oxidation. A chamber in which the equipment to be cleaned is positioned is adapted with gas circulating ductwork and with a burner for the introduction of hot gases of controlled oxygen content.

This invention relates to combustion apparatus.

In one of its more specific aspects, this invention relates to apparatus which provides controlled combustion for the elimination of deposits on equipment.

In the course of various refining operations, certain equipment has various materials deposited on it and this necessitates the eventual cleaning of the equipment. For example, deposits tend to build up in conduit, vessels, heat exchangers, and these deposits must eventually be removed in order to attain optimum operation of the equipment concerned.

Such deposits are frequently removed by burning them from the equipment. In doing so, careful control of the combustion process must be maintained in order to prevent nonuniform temperatures or overheating of the equipment with attendant damage to it and to maintain a proper oxygen content in the hot gases to facilitate the oxidation of those substances whose removal is desired. The apparatus of this invention provides such a controlled combustion process.

According to this invention there is provided a chamber connected at its ends by circulation ductwork, a blower "positioned in connection with the ductwork to induce the circulation, a burner positioned to discharge hot gases into the chamber, preferably through the ductwork, means It is another object of this invention to provide a com understood if explained in conjunction with the attached I drawing which depicts one embodiment of the invention.

Referring now to the attached drawing, there is shown chamber 10 which is adapted through one portion of its wall with burner 21 and through another portion of its wall with ductwork 12 interconnected to blower 19, which, in turn, is connected with ductwork 20 which discharges proximate burner 21 into chamber 10.

Chamber 10 can be of any suitable size and is preferably constructed of insulated walls and closable inlet 11 through which that equipment to be cleaned is placed into the chamber. Chamber 10 is also adapted with various connections, such as steam inlet conduits 24 and 25, oxygen analyzer 27, and pressure sensing means 29.

Interconnected with chamber 10 is a system of conduit or ductwork including duct sections 12, 20 and 26. Section 3,667,744 Patented June 6, 1972 26 discharges into chamber 10 and section 12 provides means for removing the gases from chamber 10, sections 26 and 12 being preferably positioned at opposite ends of chamber 10, ductwork section 20 providing communication between section 12 and section 26. This ductwork is of conventional construction and is of sufficient size to provide for the passage of gases therethrough without undue pressure drop. The ductwork can be insulated for heat conservation or personnel protection.

Positioned preferably in a section of the ductwork at the gas inlet end of chamber 10 is burner 21. It can be operable on any available fuel and is capable of introducing hot combustion gases into the chamber to produce within the chamber temperatures sutiicient to oxidize the deposits whose removal from the equipment is desired. The burner is supplied with air and fuel through conduits 23 and 22, respectively, and the return section of conduit 20 discharges into a shielded portion of the burner, so as not to interfere with the burners flame and to aid in the introduction of the combustion gases into the chamber. It will be understood that the burner can be located to discharge directly into the chamber, other than through the ductwork; for example, the burner, or a plurality of burners can be mounted in the chamber wall and can discharge directly into the chamber.

Located within a portion of the ductwork and preferably near the outlet section 12 is positioned blower 19 which draws gases from the chamber and circulates them through the ductwork proximate the burner and back into the chamber.

When the burner is located to discharge into the ductwork, air to the burner can be aspirated thereinto or can be supplied with those gases introduced around the burner from conduit 20. In the latter method, blower 16 is supplied to introduce combustion air into section 20 of the return ductwork. Blower 16 is of conventional manufacture and may be driven, in common, with the drive for blower .19.

If the burner, or burners, is mounted in the wall of the chamber, blower 16 can be adapted to discharge through the wall of the chamber and around the burner.

Because of the continuous introduction of air and combustion gases into the system, it is necessary to continuously remove some fraction of the gases from the system. This is done through after-burner 14, the quantity thereinto being controlled by damper 30 positioned in ductwork section 13 leading thereto. Although optional, this gas is preferably disposed of through an after-burner which discharges into stack 15 inasmuch as the vented gases can contain some portion of nonoxidized materials which is preferably oxidized before venting to atmosphere. To facilitate this further oxidation, the after-burner can be supplied with fuel through conduit 31 and with air from auxiliary blower 16.

While shown as exhausting from the ductwork, the conduit which discharges the excess gases from the chamber can be positioned to exhaust directly through the wall of the chamber, the discharge being made preferably at that end opposite the introduction of the air or oxygencontaining gases.

The apparatus of this invention is equipped with certain controls which provide automatic operation of the system and which limits temperature variation to about 50 F.

These control mechanisms are integrated with, and interrelated to, their accompanying responsive mechanisms by conventional means and methods which are known in the art. Hence, this discussion will be limited to a discussion of the principal control feature and the mechanism which ultimately respond thereto.

Previously-mentioned oxygen analyzer 27 which measures the oxygen content within the chamber is interconnected to position valve 60 in the fuel conduit to burner 21"andto'position valve 61 in the air conduit in burner 21. Temperature measuring means, or thermocouple 28, is also interconnected with valves 60 and 61 to enable temperature control of the system. Relatedly, the oxygen analyzer can be interrelated to valve 62 in conduit 17 to provide for the introduction of fresh air when an increase in the oxygen content of the gases within chamber 10 is required, or'it can be interrelated with the driver of blower 16 to provide either more or less oxygen as may be required.

The amount of gases retained Within the system and, relatedly, vented through the after-burner and stack, is controlled by means of pressure controller 29 which senses the pressure in the chamber and positions valve 30 in ductwork 13 to open and vent gases in the event of high pressure or to close and allow gas and pressure buildup in the event of low pressure.

A separate temperature sensing means can be provided Within the chamber for positioning on or near the equipment being cleaned in order to prevent its being overheated. Such a temperature sensing means, as indicated by point 63, can be interrelated to control valve 60 in fuel conduit line to burner 21 to override all other controls integrated therewith to shut the burner down in case of equipment overheating.

In addition to the aforementioned controls, the system can be equipped with the usual fuel system controls, flame failure controls and other conduits and measuring devices.

For example, various steam conduits can be positioned within the chamber for providing steam flow through the equipment being cleaned or to provide steam for extinguishing unwanted burning which can take place. Similarly, audible alarms can be provided to warn of high oxygen content of the gases.

One apparatus of this invention was comprised of a chamber of semicircular configuration having about an 8 foot radius and being about 38 feet in length. Its wall was comprised of about 4 /2 inches thick, 3000 fire brick. Its circulating ductwork had a capacity of about 38,000 cubic feet/min. at 700 F. and about 2 inches w.c. loss.

The circulation blower had a capacity of 38,000 cubic feet/min. at 900 F. and 2 inches W.c. loss. The auxiliary burner had a capacity of 15,000 scfh at 21 inches w.c.

During operation, this system operated at a circulating gas temperature of up to about 1000 F., with a circulating gas oxygen content of from 2 to 5 volume percent.

It will be evident from the foreging that various modifications can be made to this invention. Such, however, are considered as being within the scope of the invention.

What is claimed is:

1. An apparatus for the removal of combustible deposits from equipment which comprises:

(a) a chamber;

(b) a duct in open communication with a first end of said chamber to discharge thereinto and in open communication with a second end of said chamber to said ductwork to induce said discharge from and into said chamber; 7 T 7 (d) a burner adapted to discharge combustion gases into said chamber;

(e) means for venting gases from said chamber responsive to thepressure therein;

(f) means for introducing oxygen-containing gases into said chambers; and Y (g) means for oxidizing the vented gases prior to their discharge to the atmosphere.

2. The apparatus as defined in claim 1 in which said burner discharges into said duct.

3. The apparatus as defined in claim 1 in which said means for venting gases from said chamber comprises a conduit discharging from said ductand discharging into an after-burner.

4. The apparatus as defined in claim 1 in which said means for introducing oxygen-containing gases into said chamber comprises a second blower adapted to discharge into said duct.

5. The apparatus as defined in claim 4 in which said second blower discharges into said means for venting gases from said chamber.

6. The apparatus as defined in claim 1 in which said chamber is adapted with oxygen determining means and is interconnected with said means for introducing oxygencontaining gases into said chamber.

7. The apparatus as defined in claim 1 in which temperature control means positioned within said chamber are interconnected with said burner to control the discharge therefrom.

8. The apparatus as defined in claim 3 in which said after-burner and said means for venting gases discharge into a stack.

9. The apparatus as defined in claim lin which said circulation means positioned in communication with said ductwork to induce said discharge from and into said chamber comprises a first blower. V p

10. The apparatus as defined in claim 1 in which said burner is positioned to discharge into said ductwork and said means for venting gases from said chamber comprises a conduit discharging into an after-burner and said means for introducing oxygen-containing gases into said chamber comprises a second blower discharging into said duct and said after-burner.

11. Theapparatus as described in claim 3 comprising a closure valve for said conduit and pressure controlling means for positioning said valves responsive to pressure within the chamber.

References Cited UNITED STATES PATENTS I 4/1930 Harrison 26319 A 3,061,294 10/1962 Ohmstede 263-43 JOHN J. CAMBY, Primary Examiner I us. 01. xa. 26319 A 

